From 9d71e9d480b813c73d537de8d2c5b78e40bc3616 Mon Sep 17 00:00:00 2001
From: Andreas Kloeckner <inform@tiker.net>
Date: Thu, 11 Jun 2009 00:57:56 -0400
Subject: [PATCH] Introduce remainder into Pymbolic's expression language.
---
pymbolic/mapper/stringifier.py | 7 ++++++
pymbolic/primitives.py | 43 +++++++++++++++++++++++++++++-----
2 files changed, 44 insertions(+), 6 deletions(-)
diff --git a/pymbolic/mapper/stringifier.py b/pymbolic/mapper/stringifier.py
index 1926414..2b79ace 100644
--- a/pymbolic/mapper/stringifier.py
+++ b/pymbolic/mapper/stringifier.py
@@ -106,6 +106,13 @@ class StringifyMapper(pymbolic.mapper.RecursiveMapper):
self.rec(expr.exponent, PREC_POWER)),
enclosing_prec, PREC_POWER)
+ def map_remainder(self, expr, enclosing_prec):
+ return self.parenthesize_if_needed(
+ self.format("%s %% %s",
+ self.rec(expr.numerator, PREC_PRODUCT),
+ self.rec(expr.denominator, PREC_POWER)), # analogous to ^{-1}
+ enclosing_prec, PREC_PRODUCT)
+
def map_polynomial(self, expr, enclosing_prec):
from pymbolic.primitives import flattened_sum
return self.rec(flattened_sum(
diff --git a/pymbolic/primitives.py b/pymbolic/primitives.py
index f16303f..7a654f1 100644
--- a/pymbolic/primitives.py
+++ b/pymbolic/primitives.py
@@ -89,6 +89,20 @@ class Expression(object):
return quotient(other, self)
__rtruediv__ = __rdiv__
+ def __mod__(self, other):
+ if not is_valid_operand(other):
+ return NotImplemented
+
+ if is_zero(other-1):
+ return self
+ return Remainder(self, other)
+
+ def __rmod(self, other):
+ if not is_valid_operand(other):
+ return NotImplemented
+
+ return Remainder(other, self)
+
def __pow__(self, other):
if not is_valid_operand(other):
return NotImplemented
@@ -442,7 +456,7 @@ class Product(Expression):
-class Quotient(Expression):
+class QuotientBase(Expression):
def __init__(self, numerator, denominator=1):
self.numerator = numerator
self.denominator = denominator
@@ -458,20 +472,37 @@ class Quotient(Expression):
def den(self):
return self.denominator
+ def __nonzero__(self):
+ return bool(self.numerator)
+
+ def get_hash(self):
+ return hash((self.__class__, self.numerator, self.denominator))
+
+
+
+
+class Quotient(QuotientBase):
def is_equal(self, other):
from pymbolic.rational import Rational
return isinstance(other, (Rational, Quotient)) \
and (self.numerator == other.numerator) \
and (self.denominator == other.denominator)
- def __nonzero__(self):
- return bool(self.numerator)
+ def get_mapper_method(self, mapper):
+ return mapper.map_quotient
- def get_hash(self):
- return hash((self.__class__, self.numerator, self.denominator))
+
+
+
+class Remainder(QuotientBase):
+ def is_equal(self, other):
+ from pymbolic.rational import Rational
+ return self.__class__ == other.__class__ \
+ and (self.numerator == other.numerator) \
+ and (self.denominator == other.denominator)
def get_mapper_method(self, mapper):
- return mapper.map_quotient
+ return mapper.map_remainder
--
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